Basics of HTTP Protocol Explained

Aug 19, 2024

Understanding HTTP Protocol

Introduction

  • Importance of HTTP for developers (backend, full stack, front-end).
  • Overview of the request-response cycle.
  • Tools used: Node.js, Express, Postman.

What is HTTP?

  • HTTP: Hypertext Transfer Protocol.
  • Responsible for communication between web servers and clients.
  • Stateless protocol: each request is independent of others.

HTTPS

  • HTTPS: Hypertext Transfer Protocol Secure.
  • Data encryption through SSL (Secure Sockets Layer) or TLS (Transport Layer Security).
  • Essential for sensitive information (e.g., credit card data).
  • Increasingly enforced on all pages of websites.

Request Methods

  1. GET: Fetch data from server.
    • Example: loading a web page, assets (CSS, images).
  2. POST: Submit data to the server.
    • Example: submitting a contact form.
  3. PUT: Update existing data on the server.
  4. DELETE: Remove data from the server.

Request and Response Structure

  • Headers: Metadata for requests and responses.
    • Common fields include:
      • Content-Type: Type of data (e.g., text/html, application/json).
      • Set-Cookie: Manages cookies sent from server to client.
  • Body: Contains data being sent or received (e.g., HTML, JSON).

HTTP Status Codes

  • Information (100-199): Request received, continuing process.
  • Success (200-299): Request successfully received, understood, and accepted.
  • Redirection (300-399): Further action must be taken.
  • Client Error (400-499): Request contains bad syntax or cannot be fulfilled.
  • Server Error (500-599): Server failed to fulfill a valid request.

Common Status Codes

  • 200: OK
  • 201: Created
  • 301: Moved Permanently
  • 304: Not Modified
  • 400: Bad Request
  • 401: Unauthorized
  • 404: Not Found
  • 500: Internal Server Error

HTTP/2

  • New version with improved performance.
  • Uses multiplexing to reduce latency and allows multiple requests/responses simultaneously.

Practical Example with Express

  • Set up a basic Express server.
  • Demonstrated GET and POST requests using Postman.
  • Explored handling request bodies, headers, and status codes.
  • Showed how to send JSON responses and manage content types.

Conclusion

  • Understanding HTTP basics is crucial for web development.
  • Practical skills using Express and Postman are beneficial for testing APIs and services.
  • Future learning: Explore more about HTTP/2 and server deployment configurations.